UnboundLocalError at /contact_us/ local variable 'form' referenced before assignment

You defined the form variable in this if request.method == 'POST': block. If you access the view with a GET request form gets not defined. 

Cause:

def contact_us(request):

   

    if request.method == 'POST':

        form = ContactForm(request.POST)

        if form.is_valid():

Resolution:

def contact_us(request):

    form = ContactForm(request.POST)

    if request.method == 'POST':

 

        if form.is_valid():